package com.datafan.dataintegration.core.util.json;

import java.io.Closeable;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import java.util.ResourceBundle;
import java.util.Set;
import org.json.JSONException;
import org.json.JSONPointer;
import org.json.JSONPointerException;
import org.json.JSONPropertyIgnore;
import org.json.JSONPropertyName;
import org.json.JSONString;
import org.json.JSONWriter;

/**
 * JSONLinkedObject.
 *
 * @author gavin
 * @since 2020/2/16 1:07 下午
 */
public class JSONLinkedObject {
    /**
     * It is sometimes more convenient and less ambiguous to have a
     * <code>NULL</code> object than to use Java's <code>null</code> value.
     * <code>JSONObject.NULL.equals(null)</code> returns <code>true</code>.
     * <code>JSONObject.NULL.toString()</code> returns <code>"null"</code>.
     */
    public static final Object NULL = new Null();

    /**
     * 有序的LinkedHashMap.
     */
    private final LinkedHashMap<String, Object> map;

    /**
     * Construct an empty JSONObject.
     */
    public JSONLinkedObject() {
        // LinkedHashMap is used on purpose to ensure that elements are unordered by
        // the specification.
        // JSON tends to be a portable transfer format to allows the container
        // implementations to rearrange their items for a faster element
        // retrieval based on associative access.
        // Therefore, an implementation mustn't rely on the order of the item.
//        this.map = new HashMap<String, Object>();
        this.map = new LinkedHashMap<String, Object>();
    }

    /**
     * Construct a JSONObject from a subset of another JSONObject. An array of
     * strings is used to identify the keys that should be copied. Missing keys
     * are ignored.
     *
     * @param jo    A JSONObject.
     * @param names An array of strings.
     */
    public JSONLinkedObject(JSONLinkedObject jo, String[] names) {
        this(names.length);
        for (int i = 0; i < names.length; i += 1) {
            try {
                this.putOnce(names[i], jo.opt(names[i]));
            } catch (Exception ignore) {
            }
        }
    }

    /**
     * Construct a JSONObject from a JSONTokener.
     *
     * @param x A JSONTokener object containing the source string.
     * @throws JSONException If there is a syntax error in the source string or a
     *                       duplicated key.
     */
    public JSONLinkedObject(JSONLinkedTokener x) throws JSONException {
        this();
        char c;
        String key;

        if (x.nextClean() != '{') {
            throw x.syntaxError("A JSONObject text must begin with '{'");
        }
        for (; ; ) {
            c = x.nextClean();
            switch (c) {
                case 0:
                    throw x.syntaxError("A JSONObject text must end with '}'");
                case '}':
                    return;
                default:
                    x.back();
                    key = x.nextValue().toString();
            }

            // The key is followed by ':'.

            c = x.nextClean();
            if (c != ':') {
                throw x.syntaxError("Expected a ':' after a key");
            }

            // Use syntaxError(..) to include error location

            if (key != null) {
                // Check if key exists
                if (this.opt(key) != null) {
                    // key already exists
                    throw x.syntaxError("Duplicate key \"" + key + "\"");
                }
                // Only add value if non-null
                Object value = x.nextValue();
                if (value != null) {
                    this.put(key, value);
                }
            }

            // Pairs are separated by ','.

            switch (x.nextClean()) {
                case ';':
                case ',':
                    if (x.nextClean() == '}') {
                        return;
                    }
                    x.back();
                    break;
                case '}':
                    return;
                default:
                    throw x.syntaxError("Expected a ',' or '}'");
            }
        }
    }

    /**
     * Construct a JSONObject from a Map.
     *
     * @param m A map object that can be used to initialize the contents of
     *          the JSONObject.
     * @throws JSONException        If a value in the map is non-finite number.
     * @throws NullPointerException If a key in the map is <code>null</code>
     */
    public JSONLinkedObject(Map<?, ?> m) {
        if (m == null) {
            this.map = new LinkedHashMap<String, Object>();
        } else {
            this.map = new LinkedHashMap<String, Object>(m.size());
            for (final Map.Entry<?, ?> e : m.entrySet()) {
                if (e.getKey() == null) {
                    throw new NullPointerException("Null key.");
                }
                final Object value = e.getValue();
                if (value != null) {
                    this.map.put(String.valueOf(e.getKey()), wrap(value));
                }
            }
        }
    }

    /**
     * Construct a JSONObject from an Object using bean getters. It reflects on
     * all of the public methods of the object. For each of the methods with no
     * parameters and a name starting with <code>"get"</code> or
     * <code>"is"</code> followed by an uppercase letter, the method is invoked,
     * and a key and the value returned from the getter method are put into the
     * new JSONObject.
     *
     * <p>The key is formed by removing the <code>"get"</code> or <code>"is"</code>
     * prefix. If the second remaining character is not upper case, then the
     * first character is converted to lower case.
     *
     * <p>Methods that are <code>static</code>, return <code>void</code>,
     * have parameters, or are "bridge" methods, are ignored.
     *
     * <p>For example, if an object has a method named <code>"getName"</code>, and
     * if the result of calling <code>object.getName()</code> is
     * <code>"Larry Fine"</code>, then the JSONObject will contain
     * <code>"name": "Larry Fine"</code>.
     *
     * <p>The {@link JSONPropertyName} annotation can be used on a bean getter to
     * override key name used in the JSONObject. For example, using the object
     * above with the <code>getName</code> method, if we annotated it with:
     * <pre>
     * &#64;JSONPropertyName("FullName")
     * public String getName() { return this.name; }
     * </pre>
     * The resulting JSON object would contain <code>"FullName": "Larry Fine"</code>
     *
     * <p>Similarly, the {@link JSONPropertyName} annotation can be used on non-
     * <code>get</code> and <code>is</code> methods. We can also override key
     * name used in the JSONObject as seen below even though the field would normally
     * be ignored:
     * <pre>
     * &#64;JSONPropertyName("FullName")
     * public String fullName() { return this.name; }
     * </pre>
     * The resulting JSON object would contain <code>"FullName": "Larry Fine"</code>
     *
     * <p>The {@link JSONPropertyIgnore} annotation can be used to force the bean property
     * to not be serialized into JSON. If both {@link JSONPropertyIgnore} and
     * {@link JSONPropertyName} are defined on the same method, a depth comparison is
     * performed and the one closest to the concrete class being serialized is used.
     * If both annotations are at the same level, then the {@link JSONPropertyIgnore}
     * annotation takes precedent and the field is not serialized.
     * For example, the following declaration would prevent the <code>getName</code>
     * method from being serialized:
     * <pre>
     * &#64;JSONPropertyName("FullName")
     * &#64;JSONPropertyIgnore
     * public String getName() { return this.name; }
     * </pre>
     *
     * @param bean An object that has getter methods that should be used to make
     *             a JSONObject.
     */
    public JSONLinkedObject(Object bean) {
        this();
        this.populateMap(bean);
    }

    /**
     * Construct a JSONObject from an Object, using reflection to find the
     * public members. The resulting JSONObject's keys will be the strings from
     * the names array, and the values will be the field values associated with
     * those keys in the object. If a key is not found or not visible, then it
     * will not be copied into the new JSONObject.
     *
     * @param object An object that has fields that should be used to make a
     *               JSONObject.
     * @param names  An array of strings, the names of the fields to be obtained
     *               from the object.
     */
    public JSONLinkedObject(Object object, String[] names) {
        this(names.length);
        Class<?> c = object.getClass();
        for (int i = 0; i < names.length; i += 1) {
            String name = names[i];
            try {
                this.putOpt(name, c.getField(name).get(object));
            } catch (Exception ignore) {
            }
        }
    }

    /**
     * Construct a JSONObject from a source JSON text string. This is the most
     * commonly used JSONObject constructor.
     *
     * @param source A string beginning with <code>{</code>&nbsp;<small>(left
     *               brace)</small> and ending with <code>}</code>
     *               &nbsp;<small>(right brace)</small>.
     * @throws JSONException If there is a syntax error in the source string or a
     *                       duplicated key.
     */
    public JSONLinkedObject(String source) throws JSONException {
        this(new JSONLinkedTokener(source));
    }

    /**
     * Construct a JSONObject from a ResourceBundle.
     *
     * @param baseName The ResourceBundle base name.
     * @param locale   The Locale to load the ResourceBundle for.
     * @throws JSONException If any JSONExceptions are detected.
     */
    public JSONLinkedObject(String baseName, Locale locale) throws JSONException {
        this();
        ResourceBundle bundle = ResourceBundle.getBundle(baseName, locale,
            Thread.currentThread().getContextClassLoader());

// Iterate through the keys in the bundle.

        Enumeration<String> keys = bundle.getKeys();
        while (keys.hasMoreElements()) {
            Object key = keys.nextElement();
            if (key != null) {

// Go through the path, ensuring that there is a nested JSONObject for each
// segment except the last. Add the value using the last segment's name into
// the deepest nested JSONObject.

                String[] path = ((String) key).split("\\.");
                int last = path.length - 1;
                JSONLinkedObject target = this;
                for (int i = 0; i < last; i += 1) {
                    String segment = path[i];
                    JSONLinkedObject nextTarget = target.optJSONObject(segment);
                    if (nextTarget == null) {
                        nextTarget = new JSONLinkedObject();
                        target.put(segment, nextTarget);
                    }
                    target = nextTarget;
                }
                target.put(path[last], bundle.getString((String) key));
            }
        }
    }

    /**
     * Constructor to specify an initial capacity of the internal map. Useful for library
     * internal calls where we know, or at least can best guess, how big this JSONObject
     * will be.
     *
     * @param initialCapacity initial capacity of the internal map.
     */
    protected JSONLinkedObject(int initialCapacity) {
        this.map = new LinkedHashMap<String, Object>(initialCapacity);
    }

    /**
     * Produce a string from a double. The string "null" will be returned if the
     * number is not finite.
     *
     * @param d A double.
     * @return A String.
     */
    public static String doubleToString(double d) {
        if (Double.isInfinite(d) || Double.isNaN(d)) {
            return "null";
        }

// Shave off trailing zeros and decimal point, if possible.

        String string = Double.toString(d);
        if (string.indexOf('.') > 0 && string.indexOf('e') < 0
            && string.indexOf('E') < 0) {
            while (string.endsWith("0")) {
                string = string.substring(0, string.length() - 1);
            }
            if (string.endsWith(".")) {
                string = string.substring(0, string.length() - 1);
            }
        }
        return string;
    }

    /**
     * Get an array of field names from a JSONObject.
     *
     * @param jo jo
     * @return An array of field names, or null if there are no names.
     */
    public static String[] getNames(JSONLinkedObject jo) {
        if (jo.isEmpty()) {
            return null;
        }
        return jo.keySet().toArray(new String[jo.length()]);
    }

    /**
     * Get an array of field names from an Object.
     *
     * @param object o
     * @return An array of field names, or null if there are no names.
     */
    public static String[] getNames(Object object) {
        if (object == null) {
            return null;
        }
        Class<?> klass = object.getClass();
        Field[] fields = klass.getFields();
        int length = fields.length;
        if (length == 0) {
            return null;
        }
        String[] names = new String[length];
        for (int i = 0; i < length; i += 1) {
            names[i] = fields[i].getName();
        }
        return names;
    }

    /**
     * Produce a string from a Number.
     *
     * @param number A Number
     * @return A String.
     * @throws JSONException If n is a non-finite number.
     */
    public static String numberToString(Number number) throws JSONException {
        if (number == null) {
            throw new JSONException("Null pointer");
        }
        testValidity(number);

        // Shave off trailing zeros and decimal point, if possible.

        String string = number.toString();
        if (string.indexOf('.') > 0 && string.indexOf('e') < 0
            && string.indexOf('E') < 0) {
            while (string.endsWith("0")) {
                string = string.substring(0, string.length() - 1);
            }
            if (string.endsWith(".")) {
                string = string.substring(0, string.length() - 1);
            }
        }
        return string;
    }

    /**
     * Searches the class hierarchy to see if the method or it's super
     * implementations and interfaces has the annotation.
     *
     * @param <A>             type of the annotation
     * @param m               method to check
     * @param annotationClass annotation to look for
     * @return the {@link Annotation} if the annotation exists on the current method or one of it's super class definitions
     */
    private static <A extends Annotation> A getAnnotation(final Method m, final Class<A> annotationClass) {
        // if we have invalid data the result is null
        if (m == null || annotationClass == null) {
            return null;
        }

        if (m.isAnnotationPresent(annotationClass)) {
            return m.getAnnotation(annotationClass);
        }

        // if we've already reached the Object class, return null;
        Class<?> c = m.getDeclaringClass();
        if (c.getSuperclass() == null) {
            return null;
        }

        // check directly implemented interfaces for the method being checked
        for (Class<?> i : c.getInterfaces()) {
            try {
                Method im = i.getMethod(m.getName(), m.getParameterTypes());
                return getAnnotation(im, annotationClass);
            } catch (final SecurityException ex) {
                continue;
            } catch (final NoSuchMethodException ex) {
                continue;
            }
        }

        try {
            return getAnnotation(
                c.getSuperclass().getMethod(m.getName(), m.getParameterTypes()),
                annotationClass);
        } catch (final SecurityException ex) {
            return null;
        } catch (final NoSuchMethodException ex) {
            return null;
        }
    }

    /**
     * Searches the class hierarchy to see if the method or it's super
     * implementations and interfaces has the annotation. Returns the depth of the
     * annotation in the hierarchy.
     *
     * @param m               method to check
     * @param annotationClass annotation to look for
     * @return Depth of the annotation or -1 if the annotation is not on the method.
     */
    private static int getAnnotationDepth(final Method m, final Class<? extends Annotation> annotationClass) {
        // if we have invalid data the result is -1
        if (m == null || annotationClass == null) {
            return -1;
        }

        if (m.isAnnotationPresent(annotationClass)) {
            return 1;
        }

        // if we've already reached the Object class, return -1;
        Class<?> c = m.getDeclaringClass();
        if (c.getSuperclass() == null) {
            return -1;
        }

        // check directly implemented interfaces for the method being checked
        for (Class<?> i : c.getInterfaces()) {
            try {
                Method im = i.getMethod(m.getName(), m.getParameterTypes());
                int d = getAnnotationDepth(im, annotationClass);
                if (d > 0) {
                    // since the annotation was on the interface, add 1
                    return d + 1;
                }
            } catch (final SecurityException ex) {
                continue;
            } catch (final NoSuchMethodException ex) {
                continue;
            }
        }

        try {
            int d = getAnnotationDepth(
                c.getSuperclass().getMethod(m.getName(), m.getParameterTypes()),
                annotationClass);
            if (d > 0) {
                // since the annotation was on the superclass, add 1
                return d + 1;
            }
            return -1;
        } catch (final SecurityException ex) {
            return -1;
        } catch (final NoSuchMethodException ex) {
            return -1;
        }
    }

    /**
     * Produce a string in double quotes with backslash sequences in all the
     * right places. A backslash will be inserted within ,producing
     * allowing JSON text to be delivered in HTML. In JSON text, a string cannot
     * contain a control character or an unescaped quote or backslash.
     *
     * @param string A String
     * @return A String correctly formatted for insertion in a JSON text.
     */
    public static String quote(String string) {
        StringWriter sw = new StringWriter();
        synchronized (sw.getBuffer()) {
            try {
                return quote(string, sw).toString();
            } catch (IOException ignored) {
                // will never happen - we are writing to a string writer
                return "";
            }
        }
    }

    /**
     * quote.
     *
     * @param string str
     * @param w      write
     * @return write
     * @throws IOException error
     */
    public static Writer quote(String string, Writer w) throws IOException {
        if (string == null || string.isEmpty()) {
            w.write("\"\"");
            return w;
        }

        char b;
        char c = 0;
        String hhhh;
        int i;
        int len = string.length();

        w.write('"');
        for (i = 0; i < len; i += 1) {
            b = c;
            c = string.charAt(i);
            switch (c) {
                case '\\':
                case '"':
                    w.write('\\');
                    w.write(c);
                    break;
                case '/':
                    if (b == '<') {
                        w.write('\\');
                    }
                    w.write(c);
                    break;
                case '\b':
                    w.write("\\b");
                    break;
                case '\t':
                    w.write("\\t");
                    break;
                case '\n':
                    w.write("\\n");
                    break;
                case '\f':
                    w.write("\\f");
                    break;
                case '\r':
                    w.write("\\r");
                    break;
                default:
                    if (c < ' ' || (c >= '\u0080' && c < '\u00a0') || (c >= '\u2000' && c < '\u2100')) {
                        w.write("\\u");
                        hhhh = Integer.toHexString(c);
                        w.write("0000", 0, 4 - hhhh.length());
                        w.write(hhhh);
                    } else {
                        w.write(c);
                    }
            }
        }
        w.write('"');
        return w;
    }

    /**
     * Tests if the value should be tried as a decimal. It makes no test if there are actual digits.
     *
     * @param val value to test
     * @return true if the string is "-0" or if it contains '.', 'e', or 'E', false otherwise.
     */
    protected static boolean isDecimalNotation(final String val) {
        return val.indexOf('.') > -1 || val.indexOf('e') > -1
            || val.indexOf('E') > -1 || "-0".equals(val);
    }

    /**
     * Converts a string to a number using the narrowest possible type. Possible
     * returns for this function are BigDecimal, Double, BigInteger, Long, and Integer.
     * When a Double is returned, it should always be a valid Double and not NaN or +-infinity.
     *
     * @param val value to convert
     * @return Number representation of the value.
     * @throws NumberFormatException thrown if the value is not a valid number. A public
     *                               caller should catch this and wrap it in a {@link JSONException} if applicable.
     */
    protected static Number stringToNumber(final String val) throws NumberFormatException {
        char initial = val.charAt(0);
        if ((initial >= '0' && initial <= '9') || initial == '-') {
            // decimal representation
            if (isDecimalNotation(val)) {
                // quick dirty way to see if we need a BigDecimal instead of a Double
                // this only handles some cases of overflow or underflow
                if (val.length() > 14) {
                    return new BigDecimal(val);
                }
                final Double d = Double.valueOf(val);
                if (d.isInfinite() || d.isNaN()) {
                    // if we can't parse it as a double, go up to BigDecimal
                    // this is probably due to underflow like 4.32e-678
                    // or overflow like 4.65e5324. The size of the string is small
                    // but can't be held in a Double.
                    return new BigDecimal(val);
                }
                return d;
            }
            // integer representation.
            // This will narrow any values to the smallest reasonable Object representation
            // (Integer, Long, or BigInteger)

            // string version
            // The compare string length method reduces GC,
            // but leads to smaller integers being placed in larger wrappers even though not
            // needed. i.e. 1,000,000,000 -> Long even though it's an Integer
            // 1,000,000,000,000,000,000 -> BigInteger even though it's a Long
            //if(val.length()<=9){
            //    return Integer.valueOf(val);
            //}
            //if(val.length()<=18){
            //    return Long.valueOf(val);
            //}
            //return new BigInteger(val);

            // BigInteger version: We use a similar bitLenth compare as
            // BigInteger#intValueExact uses. Increases GC, but objects hold
            // only what they need. i.e. Less runtime overhead if the value is
            // long lived. Which is the better tradeoff? This is closer to what's
            // in stringToValue.
            BigInteger bi = new BigInteger(val);
            if (bi.bitLength() <= 31) {
                return Integer.valueOf(bi.intValue());
            }
            if (bi.bitLength() <= 63) {
                return Long.valueOf(bi.longValue());
            }
            return bi;
        }
        throw new NumberFormatException("val [" + val + "] is not a valid number.");
    }

    /**
     * Try to convert a string into a number, boolean, or null. If the string
     * can't be converted, return the string.
     *
     * @param string A String.
     * @return A simple JSON value.
     */
    // Changes to this method must be copied to the corresponding method in
    // the XML class to keep full support for Android
    public static Object stringToValue(String string) {
        if ("".equals(string)) {
            return string;
        }
        if ("true".equalsIgnoreCase(string)) {
            return Boolean.TRUE;
        }
        if ("false".equalsIgnoreCase(string)) {
            return Boolean.FALSE;
        }
        if ("null".equalsIgnoreCase(string)) {
            return JSONLinkedObject.NULL;
        }

        /*
         * If it might be a number, try converting it. If a number cannot be
         * produced, then the value will just be a string.
         */

        char initial = string.charAt(0);
        if ((initial >= '0' && initial <= '9') || initial == '-') {
            try {
                // if we want full Big Number support this block can be replaced with:
                // return stringToNumber(string);
                if (isDecimalNotation(string)) {
                    Double d = Double.valueOf(string);
                    if (!d.isInfinite() && !d.isNaN()) {
                        return d;
                    }
                } else {
                    Long myLong = Long.valueOf(string);
                    if (string.equals(myLong.toString())) {
                        if (myLong.longValue() == myLong.intValue()) {
                            return Integer.valueOf(myLong.intValue());
                        }
                        return myLong;
                    }
                }
            } catch (Exception ignore) {
            }
        }
        return string;
    }

    /**
     * Throw an exception if the object is a NaN or infinite number.
     *
     * @param o The object to test.
     * @throws JSONException If o is a non-finite number.
     */
    public static void testValidity(Object o) throws JSONException {
        if (o != null) {
            if (o instanceof Double) {
                if (((Double) o).isInfinite() || ((Double) o).isNaN()) {
                    throw new JSONException(
                        "JSON does not allow non-finite numbers.");
                }
            } else if (o instanceof Float) {
                if (((Float) o).isInfinite() || ((Float) o).isNaN()) {
                    throw new JSONException(
                        "JSON does not allow non-finite numbers.");
                }
            }
        }
    }

    /**
     * Make a JSON text of an Object value. If the object has an
     * value.toJSONString() method, then that method will be used to produce the
     * JSON text. The method is required to produce a strictly conforming text.
     * If the object does not contain a toJSONString method (which is the most
     * common case), then a text will be produced by other means. If the value
     * is an array or Collection, then a JSONArray will be made from it and its
     * toJSONString method will be called. If the value is a MAP, then a
     * JSONObject will be made from it and its toJSONString method will be
     * called. Otherwise, the value's toString method will be called, and the
     * result will be quoted.
     * Warning: This method assumes that the data structure is acyclical.
     *
     * @param value The value to be serialized.
     * @return a printable, displayable, transmittable representation of the object, beginning with.
     * @throws JSONException If the value is or contains an invalid number.
     */
    public static String valueToString(Object value) throws JSONException {
        // moves the implementation to JSONWriter as:
        // 1. It makes more sense to be part of the writer class
        // 2. For Android support this method is not available. By implementing it in the Writer
        //    Android users can use the writer with the built in Android JSONObject implementation.
        return JSONWriter.valueToString(value);
    }

    /**
     * Wrap an object, if necessary. If the object is <code>null</code>, return the NULL
     * object. If it is an array or collection, wrap it in a JSONArray. If it is
     * a map, wrap it in a JSONObject. If it is a standard property (Double,
     * String, et al) then it is already wrapped. Otherwise, if it comes from
     * one of the java packages, turn it into a string. And if it doesn't, try
     * to wrap it in a JSONObject. If the wrapping fails, then null is returned.
     *
     * @param object The object to wrap
     * @return The wrapped value
     */
    public static Object wrap(Object object) {
        try {
            if (object == null) {
                return NULL;
            }
            if (object instanceof JSONLinkedObject || object instanceof com.datafan.dataintegration.core.util.json.JSONArray
                || NULL.equals(object) || object instanceof JSONString
                || object instanceof Byte || object instanceof Character
                || object instanceof Short || object instanceof Integer
                || object instanceof Long || object instanceof Boolean
                || object instanceof Float || object instanceof Double
                || object instanceof String || object instanceof BigInteger
                || object instanceof BigDecimal || object instanceof Enum) {
                return object;
            }

            if (object instanceof Collection) {
                Collection<?> coll = (Collection<?>) object;
                return new com.datafan.dataintegration.core.util.json.JSONArray(coll);
            }
            if (object.getClass().isArray()) {
                return new com.datafan.dataintegration.core.util.json.JSONArray(object);
            }
            if (object instanceof Map) {
                Map<?, ?> map = (Map<?, ?>) object;
                return new JSONLinkedObject(map);
            }
            Package objectPackage = object.getClass().getPackage();
            String objectPackageName = objectPackage != null ? objectPackage
                .getName() : "";
            if (objectPackageName.startsWith("java.")
                || objectPackageName.startsWith("javax.")
                || object.getClass().getClassLoader() == null) {
                return object.toString();
            }
            return new JSONLinkedObject(object);
        } catch (Exception exception) {
            return null;
        }
    }

    static final Writer writeValue(Writer writer, Object value,
                                   int indentFactor, int indent) throws JSONException, IOException {
        if (value == null || value.equals(null)) {
            writer.write("null");
        } else if (value instanceof JSONString) {
            Object o;
            try {
                o = ((JSONString) value).toJSONString();
            } catch (Exception e) {
                throw new JSONException(e);
            }
            writer.write(o != null ? o.toString() : quote(value.toString()));
        } else if (value instanceof Number) {
            // not all Numbers may match actual JSON Numbers. i.e. fractions or Imaginary
            final String numberAsString = numberToString((Number) value);
            try {
                // Use the BigDecimal constructor for its parser to validate the format.
                @SuppressWarnings("unused")
                BigDecimal testNum = new BigDecimal(numberAsString);
                // Close enough to a JSON number that we will use it unquoted
                writer.write(numberAsString);
            } catch (NumberFormatException ex) {
                // The Number value is not a valid JSON number.
                // Instead we will quote it as a string
                quote(numberAsString, writer);
            }
        } else if (value instanceof Boolean) {
            writer.write(value.toString());
        } else if (value instanceof Enum<?>) {
            writer.write(quote(((Enum<?>) value).name()));
        } else if (value instanceof JSONLinkedObject) {
            ((JSONLinkedObject) value).write(writer, indentFactor, indent);
        } else if (value instanceof com.datafan.dataintegration.core.util.json.JSONArray) {
            ((com.datafan.dataintegration.core.util.json.JSONArray) value).write(writer, indentFactor, indent);
        } else if (value instanceof Map) {
            Map<?, ?> map = (Map<?, ?>) value;
            new JSONLinkedObject(map).write(writer, indentFactor, indent);
        } else if (value instanceof Collection) {
            Collection<?> coll = (Collection<?>) value;
            new com.datafan.dataintegration.core.util.json.JSONArray(coll).write(writer, indentFactor, indent);
        } else if (value.getClass().isArray()) {
            new com.datafan.dataintegration.core.util.json.JSONArray(value).write(writer, indentFactor, indent);
        } else {
            quote(value.toString(), writer);
        }
        return writer;
    }

    static final void indent(Writer writer, int indent) throws IOException {
        for (int i = 0; i < indent; i += 1) {
            writer.write(' ');
        }
    }

    /**
     * Accumulate values under a key. It is similar to the put method except
     * that if there is already an object stored under the key then a JSONArray
     * is stored under the key to hold all of the accumulated values. If there
     * is already a JSONArray, then the new value is appended to it. In
     * contrast, the put method replaces the previous value.
     * If only one value is accumulated that is not a JSONArray, then the result
     * will be the same as using put. But if multiple values are accumulated,
     * then the result will be like append.
     *
     * @param key   A key string.
     * @param value An object to be accumulated under the key.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject accumulate(String key, Object value) throws JSONException {
        testValidity(value);
        Object object = this.opt(key);
        if (object == null) {
            this.put(key,
                value instanceof com.datafan.dataintegration.core.util.json.JSONArray ? new com.datafan.dataintegration.core.util.json.JSONArray().put(value)
                    : value);
        } else if (object instanceof com.datafan.dataintegration.core.util.json.JSONArray) {
            ((com.datafan.dataintegration.core.util.json.JSONArray) object).put(value);
        } else {
            this.put(key, new com.datafan.dataintegration.core.util.json.JSONArray().put(object).put(value));
        }
        return this;
    }

    /**
     * Append values to the array under a key. If the key does not exist in the
     * JSONObject, then the key is put in the JSONObject with its value being a
     * JSONArray containing the value parameter. If the key was already
     * associated with a JSONArray, then the value parameter is appended to it.
     *
     * @param key   A key string.
     * @param value An object to be accumulated under the key.
     * @return this.
     * @throws JSONException If the value is non-finite number or if the current value associated with
     *                       the key is not a JSONArray.
     */
    public JSONLinkedObject append(String key, Object value) throws JSONException {
        testValidity(value);
        Object object = this.opt(key);
        if (object == null) {
            this.put(key, new com.datafan.dataintegration.core.util.json.JSONArray().put(value));
        } else if (object instanceof com.datafan.dataintegration.core.util.json.JSONArray) {
            this.put(key, ((com.datafan.dataintegration.core.util.json.JSONArray) object).put(value));
        } else {
            throw new JSONException("JSONObject[" + key
                + "] is not a JSONArray.");
        }
        return this;
    }

    /**
     * Get the value object associated with a key.
     *
     * @param key A key string.
     * @return The object associated with the key.
     * @throws JSONException if the key is not found.
     */
    public Object get(String key) throws JSONException {
        if (key == null) {
            throw new JSONException("Null key.");
        }
        Object object = this.opt(key);
        if (object == null) {
            throw new JSONException("JSONObject[" + quote(key) + "] not found.");
        }
        return object;
    }

    /**
     * Get the enum value associated with a key.
     *
     * @param clazz The type of enum to retrieve.
     * @param key   A key string.
     * @param <E>   e
     * @return The enum value associated with the key
     * @throws JSONException if the key is not found or if the value cannot be converted
     *                       to an enum.
     */
    public <E extends Enum<E>> E getEnum(Class<E> clazz, String key) throws JSONException {
        E val = optEnum(clazz, key);
        if (val == null) {
            // JSONException should really take a throwable argument.
            // If it did, I would re-implement this with the Enum.valueOf
            // method and place any thrown exception in the JSONException
            throw new JSONException("JSONObject[" + quote(key)
                + "] is not an enum of type " + quote(clazz.getSimpleName())
                + ".");
        }
        return val;
    }

    /**
     * Get the boolean value associated with a key.
     *
     * @param key A key string.
     * @return The truth.
     * @throws JSONException if the value is not a Boolean or the String "true" or
     *                       "false".
     */
    public boolean getBoolean(String key) throws JSONException {
        Object object = this.get(key);
        if (object.equals(Boolean.FALSE)
            || (object instanceof String && ((String) object)
            .equalsIgnoreCase("false"))) {
            return false;
        } else if (object.equals(Boolean.TRUE)
            || (object instanceof String && ((String) object)
            .equalsIgnoreCase("true"))) {
            return true;
        }
        throw new JSONException("JSONObject[" + quote(key)
            + "] is not a Boolean.");
    }

    /**
     * Get the BigInteger value associated with a key.
     *
     * @param key A key string.
     * @return The numeric value.
     * @throws JSONException if the key is not found or if the value cannot
     *                       be converted to BigInteger.
     */
    public BigInteger getBigInteger(String key) throws JSONException {
        Object object = this.get(key);
        try {
            return new BigInteger(object.toString());
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] could not be converted to BigInteger.", e);
        }
    }

    /**
     * Get the BigDecimal value associated with a key.
     *
     * @param key A key string.
     * @return The numeric value.
     * @throws JSONException if the key is not found or if the value
     *                       cannot be converted to BigDecimal.
     */
    public BigDecimal getBigDecimal(String key) throws JSONException {
        Object object = this.get(key);
        if (object instanceof BigDecimal) {
            return (BigDecimal) object;
        }
        try {
            return new BigDecimal(object.toString());
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] could not be converted to BigDecimal.", e);
        }
    }

    /**
     * Get the double value associated with a key.
     *
     * @param key A key string.
     * @return The numeric value.
     * @throws JSONException if the key is not found or if the value is not a Number
     *                       object and cannot be converted to a number.
     */
    public double getDouble(String key) throws JSONException {
        Object object = this.get(key);
        try {
            return object instanceof Number ? ((Number) object).doubleValue()
                : Double.parseDouble(object.toString());
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] is not a number.", e);
        }
    }

    /**
     * Get the float value associated with a key.
     *
     * @param key A key string.
     * @return The numeric value.
     * @throws JSONException if the key is not found or if the value is not a Number
     *                       object and cannot be converted to a number.
     */
    public float getFloat(String key) throws JSONException {
        Object object = this.get(key);
        try {
            return object instanceof Number ? ((Number) object).floatValue()
                : Float.parseFloat(object.toString());
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] is not a number.", e);
        }
    }

    /**
     * Get the Number value associated with a key.
     *
     * @param key A key string.
     * @return The numeric value.
     * @throws JSONException if the key is not found or if the value is not a Number
     *                       object and cannot be converted to a number.
     */
    public Number getNumber(String key) throws JSONException {
        Object object = this.get(key);
        try {
            if (object instanceof Number) {
                return (Number) object;
            }
            return stringToNumber(object.toString());
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] is not a number.", e);
        }
    }

    /**
     * Get the int value associated with a key.
     *
     * @param key A key string.
     * @return The integer value.
     * @throws JSONException if the key is not found or if the value cannot be converted
     *                       to an integer.
     */
    public int getInt(String key) throws JSONException {
        Object object = this.get(key);
        try {
            return object instanceof Number ? ((Number) object).intValue()
                : Integer.parseInt((String) object);
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] is not an int.", e);
        }
    }

    /**
     * Get the JSONArray value associated with a key.
     *
     * @param key A key string.
     * @return A JSONArray which is the value.
     * @throws JSONException if the key is not found or if the value is not a JSONArray.
     */
    public com.datafan.dataintegration.core.util.json.JSONArray getJSONArray(String key) throws JSONException {
        Object object = this.get(key);
        if (object instanceof com.datafan.dataintegration.core.util.json.JSONArray) {
            return (com.datafan.dataintegration.core.util.json.JSONArray) object;
        }
        throw new JSONException("JSONObject[" + quote(key)
            + "] is not a JSONArray.");
    }

    /**
     * Get the JSONObject value associated with a key.
     *
     * @param key A key string.
     * @return A JSONObject which is the value.
     * @throws JSONException if the key is not found or if the value is not a JSONObject.
     */
    public JSONLinkedObject getJSONObject(String key) throws JSONException {
        Object object = this.get(key);
        if (object instanceof JSONLinkedObject) {
            return (JSONLinkedObject) object;
        }
        throw new JSONException("JSONObject[" + quote(key)
            + "] is not a JSONObject.");
    }

    /**
     * Get the long value associated with a key.
     *
     * @param key A key string.
     * @return The long value.
     * @throws JSONException if the key is not found or if the value cannot be converted
     *                       to a long.
     */
    public long getLong(String key) throws JSONException {
        Object object = this.get(key);
        try {
            return object instanceof Number ? ((Number) object).longValue()
                : Long.parseLong((String) object);
        } catch (Exception e) {
            throw new JSONException("JSONObject[" + quote(key)
                + "] is not a long.", e);
        }
    }

    /**
     * Get the string associated with a key.
     *
     * @param key A key string.
     * @return A string which is the value.
     * @throws JSONException if there is no string value for the key.
     */
    public String getString(String key) throws JSONException {
        Object object = this.get(key);
        if (object instanceof String) {
            return (String) object;
        }
        throw new JSONException("JSONObject[" + quote(key) + "] not a string.");
    }

    /**
     * Determine if the JSONObject contains a specific key.
     *
     * @param key A key string.
     * @return true if the key exists in the JSONObject.
     */
    public boolean has(String key) {
        return this.map.containsKey(key);
    }

    /**
     * Increment a property of a JSONObject. If there is no such property,
     * create one with a value of 1. If there is such a property, and if it is
     * an Integer, Long, Double, or Float, then add one to it.
     *
     * @param key A key string.
     * @return this.
     * @throws JSONException If there is already a property with this name that is not an
     *                       Integer, Long, Double, or Float.
     */
    public JSONLinkedObject increment(String key) throws JSONException {
        Object value = this.opt(key);
        if (value == null) {
            this.put(key, 1);
        } else if (value instanceof BigInteger) {
            this.put(key, ((BigInteger) value).add(BigInteger.ONE));
        } else if (value instanceof BigDecimal) {
            this.put(key, ((BigDecimal) value).add(BigDecimal.ONE));
        } else if (value instanceof Integer) {
            this.put(key, ((Integer) value).intValue() + 1);
        } else if (value instanceof Long) {
            this.put(key, ((Long) value).longValue() + 1L);
        } else if (value instanceof Double) {
            this.put(key, ((Double) value).doubleValue() + 1.0d);
        } else if (value instanceof Float) {
            this.put(key, ((Float) value).floatValue() + 1.0f);
        } else {
            throw new JSONException("Unable to increment [" + quote(key) + "].");
        }
        return this;
    }

    /**
     * Determine if the value associated with the key is <code>null</code> or if there is no
     * value.
     *
     * @param key A key string.
     * @return true if there is no value associated with the key or if the value is the JSONObject.NULL object.
     */
    public boolean isNull(String key) {
        return JSONLinkedObject.NULL.equals(this.opt(key));
    }

    /**
     * Get an enumeration of the keys of the JSONObject. Modifying this key Set will also
     * modify the JSONObject. Use with caution.
     *
     * @return An iterator of the keys.
     * @see Set#iterator()
     */
    public Iterator<String> keys() {
        return this.keySet().iterator();
    }

    /**
     * Get a set of keys of the JSONObject. Modifying this key Set will also modify the
     * JSONObject. Use with caution.
     *
     * @return A keySet.
     * @see Map#keySet()
     */
    public Set<String> keySet() {
        return this.map.keySet();
    }

    /**
     * Get a set of entries of the JSONObject. These are raw values and may not
     * match what is returned by the JSONObject get* and opt* functions. Modifying
     * the returned EntrySet or the Entry objects contained therein will modify the
     * backing JSONObject. This does not return a clone or a read-only view.
     *
     * <p>Use with caution.
     *
     * @return An Entry Set
     * @see Map#entrySet()
     */
    protected Set<Map.Entry<String, Object>> entrySet() {
        return this.map.entrySet();
    }

    /**
     * Get the number of keys stored in the JSONObject.
     *
     * @return The number of keys in the JSONObject.
     */
    public int length() {
        return this.map.size();
    }

    /**
     * Check if JSONObject is empty.
     *
     * @return true if JSONObject is empty, otherwise false.
     */
    public boolean isEmpty() {
        return map.isEmpty();
    }

    /**
     * Produce a JSONArray containing the names of the elements of this
     * JSONObject.
     *
     * @return A JSONArray containing the key strings, or null if the JSONObject is empty.
     */
    public com.datafan.dataintegration.core.util.json.JSONArray names() {
        if (this.map.isEmpty()) {
            return null;
        }
        return new com.datafan.dataintegration.core.util.json.JSONArray(this.map.keySet());
    }

    /**
     * Get an optional value associated with a key.
     *
     * @param key A key string.
     * @return An object which is the value, or null if there is no value.
     */
    public Object opt(String key) {
        return key == null ? null : this.map.get(key);
    }

    /**
     * Get the enum value associated with a key.
     *
     * @param clazz The type of enum to retrieve.
     * @param key   A key string.
     * @param <E>   e
     * @return The enum value associated with the key or null if not found
     */
    public <E extends Enum<E>> E optEnum(Class<E> clazz, String key) {
        return this.optEnum(clazz, key, null);
    }

    /**
     * Get the enum value associated with a key.
     *
     * @param clazz        The type of enum to retrieve.
     * @param key          A key string.
     * @param defaultValue The default in case the value is not found
     * @param <E>          e
     * @return The enum value associated with the key or defaultValue if the value is not found or cannot be assigned to <code>clazz</code>
     */
    public <E extends Enum<E>> E optEnum(Class<E> clazz, String key, E defaultValue) {
        try {
            Object val = this.opt(key);
            if (NULL.equals(val)) {
                return defaultValue;
            }
            if (clazz.isAssignableFrom(val.getClass())) {
                // we just checked it!
                @SuppressWarnings("unchecked")
                E myE = (E) val;
                return myE;
            }
            return Enum.valueOf(clazz, val.toString());
        } catch (IllegalArgumentException e) {
            return defaultValue;
        } catch (NullPointerException e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional boolean associated with a key. It returns false if there
     * is no such key, or if the value is not Boolean.TRUE or the String "true".
     *
     * @param key A key string.
     * @return The truth.
     */
    public boolean optBoolean(String key) {
        return this.optBoolean(key, false);
    }

    /**
     * Get an optional boolean associated with a key. It returns the
     * defaultValue if there is no such key, or if it is not a Boolean or the
     * String "true" or "false" (case insensitive).
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return The truth.
     */
    public boolean optBoolean(String key, boolean defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof Boolean) {
            return ((Boolean) val).booleanValue();
        }
        try {
            // we'll use the get anyway because it does string conversion.
            return this.getBoolean(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional BigDecimal associated with a key, or the defaultValue if
     * there is no such key or if its value is not a number. If the value is a
     * string, an attempt will be made to evaluate it as a number.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public BigDecimal optBigDecimal(String key, BigDecimal defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof BigDecimal) {
            return (BigDecimal) val;
        }
        if (val instanceof BigInteger) {
            return new BigDecimal((BigInteger) val);
        }
        if (val instanceof Double || val instanceof Float) {
            return new BigDecimal(((Number) val).doubleValue());
        }
        if (val instanceof Long || val instanceof Integer
            || val instanceof Short || val instanceof Byte) {
            return new BigDecimal(((Number) val).longValue());
        }
        // don't check if it's a string in case of unchecked Number subclasses
        try {
            return new BigDecimal(val.toString());
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional BigInteger associated with a key, or the defaultValue if
     * there is no such key or if its value is not a number. If the value is a
     * string, an attempt will be made to evaluate it as a number.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public BigInteger optBigInteger(String key, BigInteger defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof BigInteger) {
            return (BigInteger) val;
        }
        if (val instanceof BigDecimal) {
            return ((BigDecimal) val).toBigInteger();
        }
        if (val instanceof Double || val instanceof Float) {
            return new BigDecimal(((Number) val).doubleValue()).toBigInteger();
        }
        if (val instanceof Long || val instanceof Integer
            || val instanceof Short || val instanceof Byte) {
            return BigInteger.valueOf(((Number) val).longValue());
        }
        // don't check if it's a string in case of unchecked Number subclasses
        try {
            // the other opt functions handle implicit conversions, i.e.
            // jo.put("double",1.1d);
            // jo.optInt("double"); -- will return 1, not an error
            // this conversion to BigDecimal then to BigInteger is to maintain
            // that type cast support that may truncate the decimal.
            final String valStr = val.toString();
            if (isDecimalNotation(valStr)) {
                return new BigDecimal(valStr).toBigInteger();
            }
            return new BigInteger(valStr);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * Get an optional double associated with a key, or NaN if there is no such
     * key or if its value is not a number. If the value is a string, an attempt
     * will be made to evaluate it as a number.
     *
     * @param key A string which is the key.
     * @return An object which is the value.
     */
    public double optDouble(String key) {
        return this.optDouble(key, Double.NaN);
    }

    /**
     * Get an optional double associated with a key, or the defaultValue if
     * there is no such key or if its value is not a number. If the value is a
     * string, an attempt will be made to evaluate it as a number.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public double optDouble(String key, double defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof Number) {
            return ((Number) val).doubleValue();
        }
        if (val instanceof String) {
            try {
                return Double.parseDouble((String) val);
            } catch (Exception e) {
                return defaultValue;
            }
        }
        return defaultValue;
    }

    /**
     * Get the optional double value associated with an index. NaN is returned
     * if there is no value for the index, or if the value is not a number and
     * cannot be converted to a number.
     *
     * @param key A key string.
     * @return The value.
     */
    public float optFloat(String key) {
        return this.optFloat(key, Float.NaN);
    }

    /**
     * Get the optional double value associated with an index. The defaultValue
     * is returned if there is no value for the index, or if the value is not a
     * number and cannot be converted to a number.
     *
     * @param key          A key string.
     * @param defaultValue The default value.
     * @return The value.
     */
    public float optFloat(String key, float defaultValue) {
        Object val = this.opt(key);
        if (JSONLinkedObject.NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof Number) {
            return ((Number) val).floatValue();
        }
        if (val instanceof String) {
            try {
                return Float.parseFloat((String) val);
            } catch (Exception e) {
                return defaultValue;
            }
        }
        return defaultValue;
    }

    /**
     * Get an optional int value associated with a key, or zero if there is no
     * such key or if the value is not a number. If the value is a string, an
     * attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @return An object which is the value.
     */
    public int optInt(String key) {
        return this.optInt(key, 0);
    }

    /**
     * Get an optional int value associated with a key, or the default if there
     * is no such key or if the value is not a number. If the value is a string,
     * an attempt will be made to evaluate it as a number.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public int optInt(String key, int defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof Number) {
            return ((Number) val).intValue();
        }

        if (val instanceof String) {
            try {
                return new BigDecimal((String) val).intValue();
            } catch (Exception e) {
                return defaultValue;
            }
        }
        return defaultValue;
    }

    /**
     * Get an optional JSONArray associated with a key. It returns null if there
     * is no such key, or if its value is not a JSONArray.
     *
     * @param key A key string.
     * @return A JSONArray which is the value.
     */
    public com.datafan.dataintegration.core.util.json.JSONArray optJSONArray(String key) {
        Object o = this.opt(key);
        return o instanceof com.datafan.dataintegration.core.util.json.JSONArray ? (com.datafan.dataintegration.core.util.json.JSONArray) o : null;
    }

    /**
     * Get an optional JSONObject associated with a key. It returns null if
     * there is no such key, or if its value is not a JSONObject.
     *
     * @param key A key string.
     * @return A JSONObject which is the value.
     */
    public JSONLinkedObject optJSONObject(String key) {
        Object object = this.opt(key);
        return object instanceof JSONLinkedObject ? (JSONLinkedObject) object : null;
    }

    /**
     * Get an optional long value associated with a key, or zero if there is no
     * such key or if the value is not a number. If the value is a string, an
     * attempt will be made to evaluate it as a number.
     *
     * @param key A key string.
     * @return An object which is the value.
     */
    public long optLong(String key) {
        return this.optLong(key, 0);
    }

    /**
     * Get an optional long value associated with a key, or the default if there
     * is no such key or if the value is not a number. If the value is a string,
     * an attempt will be made to evaluate it as a number.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public long optLong(String key, long defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof Number) {
            return ((Number) val).longValue();
        }

        if (val instanceof String) {
            try {
                return new BigDecimal((String) val).longValue();
            } catch (Exception e) {
                return defaultValue;
            }
        }
        return defaultValue;
    }

    /**
     * Get an optional {@link Number} value associated with a key, or <code>null</code>
     * if there is no such key or if the value is not a number. If the value is a string,
     * an attempt will be made to evaluate it as a number ({@link BigDecimal}). This method
     * would be used in cases where type coercion of the number value is unwanted.
     *
     * @param key A key string.
     * @return An object which is the value.
     */
    public Number optNumber(String key) {
        return this.optNumber(key, null);
    }

    /**
     * Get an optional {@link Number} value associated with a key, or the default if there
     * is no such key or if the value is not a number. If the value is a string,
     * an attempt will be made to evaluate it as a number. This method
     * would be used in cases where type coercion of the number value is unwanted.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return An object which is the value.
     */
    public Number optNumber(String key, Number defaultValue) {
        Object val = this.opt(key);
        if (NULL.equals(val)) {
            return defaultValue;
        }
        if (val instanceof Number) {
            return (Number) val;
        }

        if (val instanceof String) {
            try {
                return stringToNumber((String) val);
            } catch (Exception e) {
                return defaultValue;
            }
        }
        return defaultValue;
    }

    /**
     * Get an optional string associated with a key. It returns an empty string
     * if there is no such key. If the value is not a string and is not null,
     * then it is converted to a string.
     *
     * @param key A key string.
     * @return A string which is the value.
     */
    public String optString(String key) {
        return this.optString(key, "");
    }

    /**
     * Get an optional string associated with a key. It returns the defaultValue
     * if there is no such key.
     *
     * @param key          A key string.
     * @param defaultValue The default.
     * @return A string which is the value.
     */
    public String optString(String key, String defaultValue) {
        Object object = this.opt(key);
        return NULL.equals(object) ? defaultValue : object.toString();
    }

    /**
     * Populates the internal map of the JSONObject with the bean properties. The
     * bean can not be recursive.
     *
     * @param bean the bean
     * @see JSONLinkedObject#JSONLinkedObject(Object)
     */
    private void populateMap(Object bean) {
        Class<?> klass = bean.getClass();

        // If klass is a System class then set includeSuperClass to false.

        boolean includeSuperClass = klass.getClassLoader() != null;

        Method[] methods = includeSuperClass ? klass.getMethods() : klass.getDeclaredMethods();
        for (final Method method : methods) {
            final int modifiers = method.getModifiers();
            if (Modifier.isPublic(modifiers)
                && !Modifier.isStatic(modifiers)
                && method.getParameterTypes().length == 0
                && !method.isBridge()
                && method.getReturnType() != Void.TYPE
                && isValidMethodName(method.getName())) {
                final String key = getKeyNameFromMethod(method);
                if (key != null && !key.isEmpty()) {
                    try {
                        final Object result = method.invoke(bean);
                        if (result != null) {
                            this.map.put(key, wrap(result));
                            // we don't use the result anywhere outside of wrap
                            // if it's a resource we should be sure to close it
                            // after calling toString
                            if (result instanceof Closeable) {
                                try {
                                    ((Closeable) result).close();
                                } catch (IOException ignore) {
                                }
                            }
                        }
                    } catch (IllegalAccessException ignore) {
                    } catch (IllegalArgumentException ignore) {
                    } catch (InvocationTargetException ignore) {
                    }
                }
            }
        }
    }

    private boolean isValidMethodName(String name) {
        return !"getClass".equals(name) && !"getDeclaringClass".equals(name);
    }

    private String getKeyNameFromMethod(Method method) {
        final int ignoreDepth = getAnnotationDepth(method, JSONPropertyIgnore.class);
        if (ignoreDepth > 0) {
            final int forcedNameDepth = getAnnotationDepth(method, JSONPropertyName.class);
            if (forcedNameDepth < 0 || ignoreDepth <= forcedNameDepth) {
                // the hierarchy asked to ignore, and the nearest name override
                // was higher or non-existent
                return null;
            }
        }
        JSONPropertyName annotation = getAnnotation(method, JSONPropertyName.class);
        if (annotation != null && annotation.value() != null && !annotation.value().isEmpty()) {
            return annotation.value();
        }
        String key;
        final String name = method.getName();
        if (name.startsWith("get") && name.length() > 3) {
            key = name.substring(3);
        } else if (name.startsWith("is") && name.length() > 2) {
            key = name.substring(2);
        } else {
            return null;
        }
        // if the first letter in the key is not uppercase, then skip.
        // This is to maintain backwards compatibility before PR406
        // (https://github.com/stleary/JSON-java/pull/406/)
        if (Character.isLowerCase(key.charAt(0))) {
            return null;
        }
        if (key.length() == 1) {
            key = key.toLowerCase(Locale.ROOT);
        } else if (!Character.isUpperCase(key.charAt(1))) {
            key = key.substring(0, 1).toLowerCase(Locale.ROOT) + key.substring(1);
        }
        return key;
    }

    /**
     * Put a key/boolean pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value A boolean which is the value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, boolean value) throws JSONException {
        return this.put(key, value ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Put a key/value pair in the JSONObject, where the value will be a
     * JSONArray which is produced from a Collection.
     *
     * @param key   A key string.
     * @param value A Collection value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, Collection<?> value) throws JSONException {
        return this.put(key, new com.datafan.dataintegration.core.util.json.JSONArray(value));
    }

    /**
     * Put a key/double pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value A double which is the value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, double value) throws JSONException {
        return this.put(key, Double.valueOf(value));
    }

    /**
     * Put a key/float pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value A float which is the value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, float value) throws JSONException {
        return this.put(key, Float.valueOf(value));
    }

    /**
     * Put a key/int pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value An int which is the value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, int value) throws JSONException {
        return this.put(key, Integer.valueOf(value));
    }

    /**
     * Put a key/long pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value A long which is the value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, long value) throws JSONException {
        return this.put(key, Long.valueOf(value));
    }

    /**
     * Put a key/value pair in the JSONObject, where the value will be a
     * JSONObject which is produced from a Map.
     *
     * @param key   A key string.
     * @param value A Map value.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, Map<?, ?> value) throws JSONException {
        return this.put(key, new JSONLinkedObject(value));
    }

    /**
     * Put a key/value pair in the JSONObject. If the value is <code>null</code>, then the
     * key will be removed from the JSONObject if it is present.
     *
     * @param key   A key string.
     * @param value An object which is the value. It should be of one of these
     *              types: Boolean, Double, Integer, JSONArray, JSONObject, Long,
     *              String, or the JSONObject.NULL object.
     * @return this.
     * @throws JSONException If the value is non-finite number.
     */
    public JSONLinkedObject put(String key, Object value) throws JSONException {
        if (key == null) {
            throw new NullPointerException("Null key.");
        }
        if (value != null) {
            testValidity(value);
            this.map.put(key, value);
        } else {
            this.remove(key);
        }
        return this;
    }

    /**
     * Put a key/value pair in the JSONObject, but only if the key and the value
     * are both non-null, and only if there is not already a member with that
     * name.
     *
     * @param key   string
     * @param value object
     * @return this.
     * @throws JSONException if the key is a duplicate
     */
    public JSONLinkedObject putOnce(String key, Object value) throws JSONException {
        if (key != null && value != null) {
            if (this.opt(key) != null) {
                throw new JSONException("Duplicate key \"" + key + "\"");
            }
            return this.put(key, value);
        }
        return this;
    }

    /**
     * Put a key/value pair in the JSONObject, but only if the key and the value
     * are both non-null.
     *
     * @param key   A key string.
     * @param value An object which is the value. It should be of one of these
     *              types: Boolean, Double, Integer, JSONArray, JSONObject, Long,
     *              String, or the JSONObject.NULL object.
     * @return this.
     * @throws JSONException If the value is a non-finite number.
     */
    public JSONLinkedObject putOpt(String key, Object value) throws JSONException {
        if (key != null && value != null) {
            return this.put(key, value);
        }
        return this;
    }

    /**
     * Creates a JSONPointer using an initialization string and tries to
     * match it to an item within this JSONObject. For example, given a
     * JSONObject initialized with this document:
     * <pre>
     * {
     *     "a":{"b":"c"}
     * }
     * </pre>
     * and this JSONPointer string:
     * <pre>
     * "/a/b"
     * </pre>
     * Then this method will return the String "c".
     * A JSONPointerException may be thrown from code called by this method.
     *
     * @param jsonPointer string that can be used to create a JSONPointer
     * @return the item matched by the JSONPointer, otherwise null
     */
    public Object query(String jsonPointer) {
        return query(new JSONPointer(jsonPointer));
    }

    /**
     * Uses a user initialized JSONPointer  and tries to
     * match it to an item within this JSONObject. For example, given a
     * JSONObject initialized with this document:
     * <pre>
     * {
     *     "a":{"b":"c"}
     * }
     * </pre>
     * and this JSONPointer:
     * <pre>
     * "/a/b"
     * </pre>
     * Then this method will return the String "c".
     * A JSONPointerException may be thrown from code called by this method.
     *
     * @param jsonPointer string that can be used to create a JSONPointer
     * @return the item matched by the JSONPointer, otherwise null
     */
    public Object query(JSONPointer jsonPointer) {
        return jsonPointer.queryFrom(this);
    }

    /**
     * Queries and returns a value from this object using {@code jsonPointer}, or
     * returns null if the query fails due to a missing key.
     *
     * @param jsonPointer the string representation of the JSON pointer
     * @return the queried value or {@code null}
     * @throws IllegalArgumentException if {@code jsonPointer} has invalid syntax
     */
    public Object optQuery(String jsonPointer) {
        return optQuery(new JSONPointer(jsonPointer));
    }

    /**
     * Queries and returns a value from this object using {@code jsonPointer}, or
     * returns null if the query fails due to a missing key.
     *
     * @param jsonPointer The JSON pointer
     * @return the queried value or {@code null}
     * @throws IllegalArgumentException if {@code jsonPointer} has invalid syntax
     */
    public Object optQuery(JSONPointer jsonPointer) {
        try {
            return jsonPointer.queryFrom(this);
        } catch (JSONPointerException e) {
            return null;
        }
    }

    /**
     * Remove a name and its value, if present.
     *
     * @param key The name to be removed.
     * @return The value that was associated with the name, or null if there was no value.
     */
    public Object remove(String key) {
        return this.map.remove(key);
    }

    /**
     * Determine if two JSONObjects are similar.
     * They must contain the same set of names which must be associated with
     * similar values.
     *
     * @param other The other JSONObject
     * @return true if they are equal
     */
    public boolean similar(Object other) {
        try {
            if (!(other instanceof JSONLinkedObject)) {
                return false;
            }
            if (!this.keySet().equals(((JSONLinkedObject) other).keySet())) {
                return false;
            }
            for (final Map.Entry<String, ?> entry : this.entrySet()) {
                String name = entry.getKey();
                Object valueThis = entry.getValue();
                Object valueOther = ((JSONLinkedObject) other).get(name);
                if (valueThis == valueOther) {
                    continue;
                }
                if (valueThis == null) {
                    return false;
                }
                if (valueThis instanceof JSONLinkedObject) {
                    if (!((JSONLinkedObject) valueThis).similar(valueOther)) {
                        return false;
                    }
                } else if (valueThis instanceof com.datafan.dataintegration.core.util.json.JSONArray) {
                    if (!((com.datafan.dataintegration.core.util.json.JSONArray) valueThis).similar(valueOther)) {
                        return false;
                    }
                } else if (!valueThis.equals(valueOther)) {
                    return false;
                }
            }
            return true;
        } catch (Throwable exception) {
            return false;
        }
    }

    /**
     * Produce a JSONArray containing the values of the members of this
     * JSONObject.
     *
     * @param names A JSONArray containing a list of key strings. This determines
     *              the sequence of the values in the result.
     * @return A JSONArray of values.
     * @throws JSONException If any of the values are non-finite numbers.
     */
    public com.datafan.dataintegration.core.util.json.JSONArray toJSONArray(com.datafan.dataintegration.core.util.json.JSONArray names) throws JSONException {
        if (names == null || names.isEmpty()) {
            return null;
        }
        com.datafan.dataintegration.core.util.json.JSONArray ja = new com.datafan.dataintegration.core.util.json.JSONArray();
        for (int i = 0; i < names.length(); i += 1) {
            ja.put(this.opt(names.getString(i)));
        }
        return ja;
    }

    /**
     * Make a JSON text of this JSONObject. For compactness, no whitespace is
     * added. If this would not result in a syntactically correct JSON text,
     * then null will be returned instead.
     *
     * <p><b>
     * Warning: This method assumes that the data structure is acyclical.
     * </b>
     *
     * @return a printable, displayable, portable, transmittable representation of the object, beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;
     * <small>(right brace)</small>.
     */
    @Override
    public String toString() {
        try {
            return this.toString(0);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * Make a pretty-printed JSON text of this JSONObject.
     *
     * <p>If <code>indentFactor > 0</code> and the {@link JSONLinkedObject}
     * has only one key, then the object will be output on a single line:
     * <pre>{@code {"key": 1}}</pre>
     *
     * <p>If an object has 2 or more keys, then it will be output across
     * multiple lines: <code><pre>{
     *  "key1": 1,
     *  "key2": "value 2",
     *  "key3": 3
     * }</pre></code>
     * Warning: This method assumes that the data structure is acyclical.
     *
     * @param indentFactor The number of spaces to add to each level of indentation.
     * @return a printable, displayable, portable, transmittable representation of the object
     * @throws JSONException If the object contains an invalid number.
     */
    public String toString(int indentFactor) throws JSONException {
        StringWriter w = new StringWriter();
        synchronized (w.getBuffer()) {
            return this.write(w, indentFactor, 0).toString();
        }
    }

    /**
     * Write the contents of the JSONObject as JSON text to a writer. For
     * compactness, no whitespace is added.
     * <b>Warning: This method assumes that the data structure is acyclical.
     * </b>
     *
     * @param writer Writer
     * @return The writer.
     * @throws JSONException e
     */
    public Writer write(Writer writer) throws JSONException {
        return this.write(writer, 0, 0);
    }

    /**
     * Write the contents of the JSONObject as JSON text to a writer.
     *
     * <p>If <code>indentFactor > 0</code> and the {@link JSONLinkedObject}
     * has only one key, then the object will be output on a single line:
     * <pre>{@code {"key": 1}}</pre>
     *
     * <p>If an object has 2 or more keys, then it will be output across
     * multiple lines: <code><pre>{
     *  "key1": 1,
     *  "key2": "value 2",
     *  "key3": 3
     * }</pre></code>
     *
     * <p><b>
     * Warning: This method assumes that the data structure is acyclical.
     * </b>
     *
     * @param writer       Writes the serialized JSON
     * @param indentFactor The number of spaces to add to each level of indentation.
     * @param indent       The indentation of the top level.
     * @return The writer.
     * @throws JSONException e
     */
    public Writer write(Writer writer, int indentFactor, int indent) throws JSONException {
        try {
            boolean commanate = false;
            final int length = this.length();
            writer.write('{');

            if (length == 1) {
                final Map.Entry<String, ?> entry = this.entrySet().iterator().next();
                final String key = entry.getKey();
                writer.write(quote(key));
                writer.write(':');
                if (indentFactor > 0) {
                    writer.write(' ');
                }
                try {
                    writeValue(writer, entry.getValue(), indentFactor, indent);
                } catch (Exception e) {
                    throw new JSONException("Unable to write JSONObject value for key: " + key, e);
                }
            } else if (length != 0) {
                final int newindent = indent + indentFactor;
                for (final Map.Entry<String, ?> entry : this.entrySet()) {
                    if (commanate) {
                        writer.write(',');
                    }
                    if (indentFactor > 0) {
                        writer.write('\n');
                    }
                    indent(writer, newindent);
                    final String key = entry.getKey();
                    writer.write(quote(key));
                    writer.write(':');
                    if (indentFactor > 0) {
                        writer.write(' ');
                    }
                    try {
                        writeValue(writer, entry.getValue(), indentFactor, newindent);
                    } catch (Exception e) {
                        throw new JSONException("Unable to write JSONObject value for key: " + key, e);
                    }
                    commanate = true;
                }
                if (indentFactor > 0) {
                    writer.write('\n');
                }
                indent(writer, indent);
            }
            writer.write('}');
            return writer;
        } catch (IOException exception) {
            throw new JSONException(exception);
        }
    }

    /**
     * Returns a java.util.Map containing all of the entries in this object.
     * If an entry in the object is a JSONArray or JSONObject it will also
     * be converted.
     * Warning: This method assumes that the data structure is acyclical.
     *
     * @return a java.util.Map containing the entries of this object
     */
    public Map<String, Object> toMap() {
        Map<String, Object> results = new LinkedHashMap<String, Object>();
        for (Map.Entry<String, Object> entry : this.entrySet()) {
            Object value;
            if (entry.getValue() == null || NULL.equals(entry.getValue())) {
                value = null;
            } else if (entry.getValue() instanceof JSONLinkedObject) {
                value = ((JSONLinkedObject) entry.getValue()).toMap();
            } else if (entry.getValue() instanceof com.datafan.dataintegration.core.util.json.JSONArray) {
                value = ((JSONArray) entry.getValue()).toList();
            } else {
                value = entry.getValue();
            }
            results.put(entry.getKey(), value);
        }
        return results;
    }

    /**
     * JSONObject.NULL is equivalent to the value that JavaScript calls null,
     * whilst Java's null is equivalent to the value that JavaScript calls
     * undefined.
     */
    private static final class Null {

        /**
         * A Null object is equal to the null value and to itself.
         *
         * @param object An object to test for nullness.
         * @return true if the object parameter is the JSONObject.NULL object or null.
         */
        @Override
        public boolean equals(Object object) {
            return object == null || object == this;
        }

        /**
         * A Null object is equal to the null value and to itself.
         *
         * @return always returns 0.
         */
        @Override
        public int hashCode() {
            return 0;
        }

        /**
         * Get the "null" string value.
         *
         * @return The string "null".
         */
        @Override
        public String toString() {
            return "null";
        }
    }
}
